Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 281: A burning candle produces water and Options:
  A) Carbon (II) oxide
  B) Carbon (IV) oxide
  C) Oxygen
  D) Hydrogen
  Show Answer
  The correct answer is B .
• Question 282:

  An element X forms the following compounds with chlorine; XCl${}_4$, XCl${}_3$, XCl${}_2$. This illustrates the

  Options:
  A) law of multiple proportions
  B) law of chemical proportions
  C) law of simple proportions
  D) law of conservation of mass
  Show Answer
  The correct answer is A .
• Question 283: Which of the following reagents will confirm the presence of unsaturation in a compound? Options:
  A) Fehling's solution
  B) Bromine water
  C) Tollen's reagent
  D) Benedict's solution
  Show Answer
  The correct answer is B .
• Question 284: An example of a polysaccharides is? Options:
  A) —dextrose
  B) mannose
  C) glucose
  D) starch
  Show Answer
  The correct answer is D .
• Question 285: When pollen grains are suspended in water and viewed through a microscope, they appear to be in a state of constant but erratic motion. This is due to? Options:
  A) convection currents
  B) small changes
  C) small changes in temperature
  D) a chemical reaction between the pollen grain and water
  E) the bombardment of the pollen grains by molecules of water
  Show Answer
  The correct answer is E .
• Question 286:

  What is the concentration of a solution containing 2g of NaOH in 100cm³ of solution?

  [Na=23, O=16, H=1]

  Options:
  A) 0.05 moldm^-3
  B) 0.30 moldm^-3
  C) 0.50 moldm^-3
  D) 0.40 moldm^-3
  Show Answer
  The correct answer is C .
• Question 287:

  What is the chemical formula of rust, which is formed on the surface of iron in the presence of oxygen and moisture?

  Options:
  A) Fe${}_3$O${}_4$
  B) FeO
  C) Fe(OH)3
  D) Fe${}_2$O${}_3$
  Show Answer
  The correct answer is D .
• Question 288: An isomer of C₅H₁₂ is Options:
  A) Butane
  B) 2 – methylbutane
  C) 2 – methylpropane
  D) 2 – ethylbutane
  Show Answer
  The correct answer is B .
• Question 289: Benzene reacts with hydrogen in the presence of nickel catalyst at 180^oC to give Options:
  A) xylene
  B) toluene
  C) cyclopentane
  D) cyclohexane
  Show Answer
  The correct answer is D .
• Question 290: In the electrolysis of brine, the anode is Options:
  A) platinum
  B) copper
  C) zinc
  D) carbon
  Show Answer
  The correct answer is D .